An internal combustion engine is provided with a lubricating device to supply oil to a portion such as a sliding portion. There are some cases where this lubricating device generates sludge having a possibility of imposing various adverse influences on respective components in the internal combustion engine. The sludge is a sludged matter, and is generally generated based upon the event that a sludge precursor generated due to oxidation of oil or a sludge precursor generated based upon incomplete combustion of fuel functions as a sludge binder performing a function of binding other individuals in the oil. That is, the sludge is an unnecessary product generated due to deterioration of oil. In addition, in the internal combustion engine, various kinds of acid substances, that is, acid components tend to be easily generated based upon a blow-by gas. It is known that mixing of these acid substances with engine oil enables generation of the sludge precursor and the sludge inside the engine to be promoted. Therefore for suppressing such deterioration of the oil, various kinds of additives can generally be added to the oil.
On the other hand, such a lubricating device is generally provided with a filter for removing foreign matters such as sludge or abrasion powder from the oil. For example, Patent Literature 1 discloses a chemical filter used in a lubricating system for an internal combustion engine. According to the description of Patent Literature 1, the chemical filter can be used in a housing of an oil filter in the lubricating system for the internal combustion engine or used in a bypass portion of the oil filter to have an ion-exchange material.
In addition, Patent Literature 2 discloses a separation component for separating fuel mixed in an internal combustion engine from the engine oil. The separation component is provided with a fuel-component separation membrane, and the separation membrane is configured in such a manner that fuel is permeable but oil is not permeable, based upon a difference in a molecular size between the oil and the fuel. The fuel-component separation membrane is provided with pores each having a diameter of the degree of 0.3 to 10 nm, and is formed of a mesoporous membrane such as a zeolite membrane or a mesoporous silica membrane. Further, Patent Literature 2 discloses that the separation component is arranged inside the oil filter provided in a lubricating oil circuit including an oil pan and is arranged downstream of a filtering material incorporated in the oil filter.
Further, Patent Literature 3 discloses an oil filter provided in a lubricating oil circulation path in an internal combustion engine. The oil filter is formed of an impurity removing layer for removing impurities each having a large particle diameter, such as iron powder, from the oil and a desulfurization layer provided downstream of the impurity removing layer. The desulfurization layer is provided to remove sulfur-containing compounds from the oil. According to the description of Citation Literature 3, a mesoporous silica porous body may be used as the desulfurization layer or the powder may be used.